Articles: nerve-block.
-
Antidromically propagated action potentials can be recorded in the proximal end of the severed medial articular nerve (MAN) on mechanical stimulation of an inflamed knee in rats and are referred to as dorsal root reflex (DRR) activity. The absence of DRR activity in normal rats suggests that the activity could be the result of hyperexcitability of spinal neurons induced by inflammation. In this study, the role of spinal type 1 metabotropic glutamate (mGlu(1)) receptors in the generation of DRR activity in the MAN during acute knee inflammation was investigated. ⋯ AIDA and LY39053 had no effect on recordings in the MAN from noninflamed control animals. However, spinal administration of AIDA did suppress DRR activity generated by infusion of 4-aminopyridine (4-AP), a K(+) channel blocker, into the dorsal horn of noninflamed animals. These observations suggest that mGlu(1) receptors support the generation of DRR activity in the MAN following sensitization of spinal cord neurons.
-
Reg Anesth Pain Med · Jan 2000
The local anesthetic properties and toxicity of saxitonin homologues for rat sciatic nerve block in vivo.
Saxitoxin and its homologues are naturally occurring compounds that block the sodium channel with high potency. They have the potential for providing prolonged duration local anesthesia when coinjected with vasoconstrictors or conventional local anesthetics and are devoid of local neurotoxicity. Here, we compare sciatic nerve block with saxitoxin to those with neosaxitoxin, decarbamoyl saxitoxin, and tetrodotoxin (TTX), in a search for even safer compounds. ⋯ Substitutions on the saxitoxin nucleus result in large differences in incidence and duration of block, and toxicity. The therapeutic indices of the saxitoxins are similar; that of TTX is slightly better.
-
Paediatric anaesthesia · Jan 2000
Randomized Controlled Trial Clinical TrialAxillary block in children: single or multiple injection?
The goal of this double-blind prospective study was to compare the effect of a single injection versus multiple fractionated doses on the onset time and quality of motor and sensory block, obtained in 70 children anaesthetized with axillary block alone. The brachial plexus was identified with a peripheral nerve stimulator, and blocked with 0.5 ml.kg-1 of 1.5% lignocaine with adrenaline. In Group S (single injection), the total volume was injected after location of one nerve. ⋯ No adverse effect was observed and analgesia was prolonged for more than 4 h. We can conclude that, unlike adults, fractionated doses in chilren bring no benefit to the quality of sensory and motor block. Selective block of the musculocutaneous nerve is recommended when a surgical procedure takes place in this territory.
-
Anesthesia and analgesia · Jan 2000
Randomized Controlled Trial Clinical TrialThree-in-one blocks with ropivacaine: evaluation of sensory onset time and quality of sensory block.
The purpose of this prospective, randomized, double-blinded study was to evaluate the sensory onset time and the quality of sensory block of ropivacaine, a new long-acting local anesthetic, compared with bupivacaine, for 3-in-1 blocks. Fifty ASA physical status I-III patients undergoing hip surgery after trauma were randomly assigned to two study groups of 25 patients each. The two study groups received a 3-in-1 block with either 20 mL of ropivacaine 0.5% or 20 mL of bupivacaine 0.5%. Blocks in both groups were performed using a nerve stimulator. The sensory onset time and the quality of sensory block was assessed by pinprick test in the central sensory region of each of the three nerves and compared with the same stimulation in the contralateral leg. We used a scale from 100% (normal sensation) to 0% (no sensory sensation). We did not find significant differences in sensory onset times between the ropivacaine group and the bupivacaine group (30+/-11 vs 32+/-10 min). The quality of sensory blocks was also comparable between the study groups (19%+/-20% vs 21%+/-15%). We conclude that the sensory onset time and quality of sensory block during 3-in-1 blocks performed with ropivacaine are comparable to those with bupivacaine. Ropivacaine is described as being less potent than bupivacaine, making this local anesthetic promising for 3-in-1 blocks because of its reportedly lower incidence of cardiovascular and central nervous system complications. ⋯ Ropivacaine 0.5% has a sensory onset time and quality of sensory block during 3-in-1 blocks similar to that of bupivacaine 0.5%. Ropivacaine is described as being less potent than bupivacaine, making it a promising local anesthetic for 3-in-1 blocks because of its reportedly lower cardiovascular and central nervous system toxicity.
-
Paediatric anaesthesia · Jan 2000
Randomized Controlled Trial Clinical TrialThe efficacy of pre- versus postsurgical axillary block on postoperative pain in paediatric patients.
We compared the effects of pre- and postsurgical axillary block on pain after hand and forearm surgery in 55 children in a double-blind randomized study. The successful blocks are reported here (n=49). Children aged 1-11 years and ASA I or II were allocated randomly to receive axillary block with 2 mg.kg-1 of 0.25% bupivacaine, either after induction but before the surgery (presurgical group, n=25) or immediately after surgery, before the end of anaesthesia (postsurgical, n=24). ⋯ Additional analgesic consumption was similar in these patients in both groups. A lower isoflurane concentration was used in the presurgical group (0.68% vs 1.72%, P< 0.001). We did not demonstrate the superiority of preemptive analgesia, but our results indicate that presurgical axillary block with 0.25% bupivacaine allows the use of inhalational anaesthetics at lower concentrations while providing a reasonably painless postoperative period.